This invention relates to a railroad grade crossing using a composite of elastomeric and non-elastomeric elements, and in particular, to such a crossing which does not require mechanical fasteners.
Many highways and arterials which cross railroad tracks utilize elastomeric crossing elements, such as those disclosed in Trickel et al. U.S. Pat. No. 4,365,743. Crossings, using elastomeric elements not only are inherently smoother than crossings made from non-elastomeric materials, but maintain their smoothness much longer. Timber crossings, for example, wear quite quickly and soon present a rough crossing surface. While asphalt wears better than timber, it is difficult to compact asphalt immediately adjacent to the rails. Thus, an asphalt grade crossing soon settles adjacent to the rails which also creates a rough surface. In addition, it is difficult to prevent water from entering between the asphalt and the rails and when freezing occurs the water expands and causes deterioration of the asphalt. Concrete wears better than asphalt and does not require mechanical compaction, however, freezing is a problem with this material also. In addition, concrete grade crossings usually have metal edges which occasionally causes shorting to occur between the rails which can activate the crossing signs. Not only do elastomeric grade crossing elements provide greater smoothness, they are easier to remove than timber, concrete or asphalt which permits them to be reused when the track is brought up to grade by adding ballast and retamping.
However, grade crossings which utilize elastomeric components are quite expensive and, accordingly, it is not economically feasible to use this type of crossing for roads which are infrequently traveled. In these situations, composite crossing systems having an elastomeric element adjacent to the rails and non-elastomeric elements over the remainder of the crossing have been utilized. A composite system of this type provides many of the advantages of an elastomeric crossing at a much lower cost than a full elastomeric system. In addition, a composite system is even easier and less expensive to install and to remove than a full elastomeric system and thus facilitates repairs to the track and rail bed. One such system composite is disclosed in Hales et al. U.S. Pat. No. 4,449,666.
Rather than pouring the elastomeric portion in place between the rails and the non-elastomeric portion as is done in Hales et al., it would be simpler and less expensive to use precast elastomeric pads, similar to the pads disclosed in Trickle et al., along with precast concrete panels, similar to those that are used as crossing elements in their own right. The precast concrete panels are heavy and thus do not have to be mechanically fastened to the ties. However, the elastomeric pads are too light to rely on their own weight to keep them in place and mechanical fasteners must be used. This not only increases the installation cost but the partial pads that would be used in a composite system would be quite narrow and leave little room for fasteners.
The subject invention overcomes the foregoing shortcomings and limitations of the prior art by providing a composite crossing system with elastomeric pad units adjacent to the sides of the rails, and non-elastomeric panels over the remainder of the crossing. An interfitting joint between each elastomeric pad unit and non-elastomeric panel causes the panel to hold the pad on the ties. This joint includes an overlapping portion that angles upwardly from the ties extending towards the rail. In a preferred embodiment, the non-elastomeric panels have metal edge protectors cast in them to prevent crumbling due to the impact of vehicular traffic. In addition, the non-elastomeric panels include integral attachment devices to facilitate their being lifted into place.
The weight of the non-elastomeric panels holds the crossing elements down on the ties, and, since the crossing elements substantially fill the space between the roadway and the rails and between the rails, the elements will not move perpendicular to the rails. In a preferred embodiment, end restraints, that are attached to the ties, prevent the elements from moving parallel with the rails.
Accordingly, it is a principal object of the present invention to provide a railroad grade crossing system having elastomeric elements adjacent to both sides of the rails and non-elastomeric elements over the remainder of the crossing.
It is a further object of the subject invention to provide such a system in which the non-elastomeric elements hold the elastomeric elements down against the ties.
It is a still further object of the subject invention to provide such a system in which the nonelastomeric elements urge the elastomeric elements against the rail flanges.